def say_hi(name, lang="zh"):
    def say_hi_zh(name):
        print("你好，{}".format(name))

    def say_hi_en(name):
        print("Hello, {}".format(name))

    fn_dict = {"zh": say_hi_zh, "en": say_hi_en}
    f = fn_dict.get(lang, say_hi_zh)
    f(name)


say_hi("Yesen")
say_hi("Yesen", lang="zh")
say_hi("Yesen", lang="en")
say_hi("Yesen", lang="fr")
